Growing macroalgae at sea

Abstract

The present invention provides a practical and economical means of growing of kelp and other types of macroalgae in large quantities on and in the ocean. Through the use of catenary principles and innovative structural designs, efficient designs emerge that translate into lightweight and low-cost components. The novel design described allows cost-efficient macroalgae farming at scales and at depths unsuitable for present macroalgae farming techniques. The device and methods described present a means of farming these seaweeds for the purpose of providing food, chemical feed stocks, and a biomass suitable for the production of biofuels.

What is claimed is: 
     
       1. An apparatus for farming macroalgae in a body of water, comprising:
 longlines for supporting a growth of macroalgae; 
 a catenary line positioned such that one end of each longline is joined to the catenary line wherein the catenary line has the form of a parabola, the catenary line having two ends and the longlines closest to each end each being longer than the longlines closer to a center of the catenary line; 
 a structure connected to the ends of the catenary line to keep the catenary line taut, the structure comprising a rigid transverse structure connected only to each end of the catenary line and extending without interruption between each end of the catenary line; 
 a second catenary line positioned at opposite ends of the longlines from the catenary line, wherein the second catenary line has the form of a parabola, the second catenary line having two ends; 
 a second structure connected to the second catenary line to keep the second catenary line taut, the second structure comprising a second rigid transverse structure connected only to each end of the second catenary line and extending without interruption between each end of the catenary line; 
 a plurality of floats connected to the structure and the second structure to keep the apparatus from sinking; 
 mooring lines connected to each end of at least one of the structure and the second structure; and 
 an anchor connected to the mooring lines; 
 wherein the mooring lines connected to the anchor, the catenary line connected to the structure and the second catenary line connected to the second structure provide a support system that ensures uniform tension in neighboring longlines and the parabolic shape of the catenary line and the second catenary line. 
 
     
     
       2. The apparatus of  claim 1  further comprising:
 first and second rigid longitudinal structures positioned between ends of the rigid transverse structure and the second rigid transverse structure to keep the rigid transverse structure and the second rigid transverse structure separated. 
 
     
     
       3. The apparatus of  claim 1  wherein there is a plurality of propulsion units such that each propulsion unit is connected to the rigid transverse structure or the second rigid transverse structure. 
     
     
       4. The apparatus of  claim 1  wherein the length of each longline is precisely specified such that the catenary line and second catenary line each achieves a parabolic shape to ensure uniform tension of all of the longlines. 
     
     
       5. The apparatus of  claim 1  wherein one or more floats of the plurality of floats is positioned at an end of the structure and an end of the second structure. 
     
     
       6. An apparatus for farming macroalgae in a body of water comprising:
 longlines for supporting a growth of macroalgae; 
 a catenary line positioned such that one end of each longline is joined to the catenary line that has the form of a parabola, the catenary line having two ends and the longlines closest to each end each being longer than the longlines closer to a center of the catenary line; 
 a second catenary line positioned such that a second end of each longline is joined to the second catenary line that has the form of a parabola, the second catenary line having two ends and the longlines closest to each end each being longer than the longlines closer to a center of the catenary line; 
 a mooring line connected to each end of the catenary line and each end of the second catenary line, each of the mooring lines connected to an anchor in contact with a seabed such that the mooring lines and anchors are sufficient to keep the apparatus within a predetermined area and such that the mooring lines and anchors provide longitudinal and transverse tension forces to maintain the proper curvature of the catenary line and the second catenary line, a pre-tension in the longlines and a uniform spacing between the longlines. 
 
     
     
       7. The apparatus of  claim 6  wherein the mooring lines extend outwardly from the catenary line and the second catenary line along a straight line that is parallel to a curvature of the catenary line at the ends of the catenary line and parallel to a curvature of the second catenary line at the ends of the second catenary line. 
     
     
       8. The apparatus of  claim 6  wherein the longlines, catenary line and second catenary line define a macroalgae farm and further comprising at least one additional macroalgae farm connected to the macroalgae farm. 
     
     
       9. The apparatus of  claim 6  wherein the length of each longline is precisely specified such that the catenary line and second catenary line each achieves a parabolic shape to ensure uniform tension of all of the longlines. 
     
     
       10. The apparatus of  claim 6  wherein the spacing between the longlines is held constant by precisely specifying the distance between each attachment point on the catenary line and the second catenary line using mathematical equations for a parabola. 
     
     
       11. The apparatus of  claim 6  further comprising a plurality of floats connected to the two ends of the catenary line and the two ends of the second catenary line to keep the apparatus from sinking. 
     
     
       12. An apparatus for farming macroalgae in a body of water, comprising:
 a plurality of longlines for supporting a growth of macroalgae, the longlines being evenly spaced with respect to adjacent longlines; 
 a catenary line positioned such that one end of each longline is joined to the catenary line wherein the catenary line has the form of a parabola having a center and two ends, the spacing of the longlines along the catenary line at the join with the catenary line being at a minimum at the center of the catenary line and increasing to a maximum at an outer point on the catenary line where the last longline closest to each end joins with the catenary line, the longlines closest to each end each being longer than the longlines closer to the center of the parabola; 
 a second catenary line positioned such that a second end of each longline is joined to the second catenary line wherein the second catenary line has the form of a parabola having a center and two ends, the spacing of the longlines along the second catenary line at the join with the second catenary line being at a minimum at the center of the second catenary line and increasing to a maximum at an outer point on the second catenary line where the last longline closest to each end joins with the second catenary line, the longlines closest to each end each being longer than the longlines closer to the center of the parabola; 
 a structure connected to each end of the catenary line and each end of the second catenary end to keep the catenary line and the second catenary line taut such that the structures provide longitudinal and transverse tension forces to maintain the proper curvature of the catenary line and the second catenary line, a pre-tension in the longlines and a uniform spacing between the longlines; and 
 a plurality of floats connected to the catenary line and the second catenary line to keep the apparatus from sinking. 
 
     
     
       13. The apparatus of  claim 12  wherein the structures comprising a mooring line connected to each end of the catenary line and the second catenary line, the mooring lines each connected to an anchor in contact with a seabed such that the mooring line and anchor are sufficient to keep the apparatus within a predetermined area. 
     
     
       14. The apparatus of  claim 13  wherein the mooring lines extend outwardly from the catenary line and the second catenary line along a straight line that is parallel to a curvature of the catenary line at the ends of the catenary line and parallel to a curvature of the second catenary line at the ends of the second catenary line. 
     
     
       15. The apparatus of  claim 12  wherein the length of each longline is precisely specified such that the catenary line and second catenary line each achieves a parabolic shape to ensure uniform tension of all of the longlines. 
     
     
       16. The apparatus of  claim 12  wherein the spacing between the longlines is held constant by precisely specifying the distance between each attachment point on the catenary line and the second catenary line using mathematical equations for a parabola. 
     
     
       17. The apparatus of  claim 12  wherein the plurality of floats are positioned at the ends of the catenary line and at the ends of the second catenary line. 
     
     
       18. The apparatus of  claim 12  wherein the longlines, catenary line and second catenary line and plurality of floats define a macroalgae farm and further comprising at least one additional macroalgae farm connected to the macroalgae farm.